The invention relates to a dryer for a textile fabric web, and to a method of drying a textile fabric web.
For drying textile fabric webs, dryers are known in which one or more drums are arranged in a housing. A textile fabric web is supplied to the dryer via an opening in the dryer compartment, the textile fabric web being wrapped around a large part of the periphery of the drum and then being discharged from the dryer compartment again. Usually, fresh air is also supplied via this opening, the fresh air being heated inside the dryer compartment and mixed with the circulating air in order to be able to absorb the greatest possible amount of moisture. While the fabric web is wrapped around the drum, the mixture of circulating air and fresh air flows through the fabric web, absorbs at least some of the moisture of the fibre web and is discharged again via the interior chamber of the drum. A volumetric sub-flow from this volumetric flow is discharged as exhaust air, the moist exhaust air being discharged via channels above the drums, which as a result of the rotating drums requires elaborate and expensive sealing and a high level of maintenance. In order to avoid the suction effect from the environment of the dryer, there have subsequently been added to the dryer compartment supply lines or channels for fresh air which can be coupled, for example, to a heat exchanger for heating the fresh air.
A previously described dryer is disclosed in DE 10 2009 016 019 A1. In dryers of this design the circulation of the fresh air takes place at right angles to the withdrawal direction of the moist air, that is to say at right angles to the drum axis, with the result that the air circulation inside the dryer compartment is disrupted. A further disadvantage is that, for reasons of lack of available space, modification is often complicated and it is not possible to couple the fresh air channel to a heat exchanger. Since the dryers are positioned very close together in a row of different processing units that treat the textile fabric web in succession, there is often no room subsequently to install a channel for fresh air between the units.
DE 1 729 499 A1 discloses a perforated drum dryer having intermediate compartments arranged at the end faces of the perforated drums. Fresh air is fed to these intermediate compartments and mixed with the drying air. Some of the used exhaust air is discharged via the fan chamber. The intermediate compartment is fixedly integrated in the dryer housing and cannot be retrofitted with a heat exchanger.